After previously indicating that he wasn’t going to back either candidate this election cycle, New York Mayor Michael Bloomberg endorsed President Obama in acolumn for Bloomberg News emphasizing that — in the wake of Hurricane Sandy — he wanted a candidate who would take climate change science seriously.

Bloomberg also differed from Romney on issues of reproductive rights and gay marriage, he stated in his editorial, but kept coming back to the environment.

“One sees climate change as an urgent problem that threatens our planet; one does not. I want our president to place scientific evidence and risk management above electoral politics,” he wrote of the choice between voting for Mitt Romney and President Obama. He also stated:

Our climate is changing. And while the increase in extreme weather we have experienced in New York City and around the world may or may not be the result of it, the risk that it might be — given this week’s devastation — should compel all elected leaders to take immediate action.

Mitt Romney, he said, also has a “history of tackling climate change” but has “reversed course” from this position:

If the 1994 or 2003 version of Mitt Romney were running for president, I may well have voted for him because, like so many other independents, I have found the past four years to be, in a word, disappointing.

The Obama endorsement didn’t come easily. Both candidates had vied for the independent mayor’s support; Mitt Romney met with Bloomberg in early May. Later in the summer, the New York Times reported on a “casual conversation” the mayor had at a fundraiser where he described his hesitance to support a candidate:

Mr. Bloomberg said that he believed Mr. Romney would probably be better at running the country than Mr. Obama, according to two guests.

But Mr. Bloomberg said he could not support Mr. Romney because he disagreed with him on so many social issues, these two people said. The mayor mentioned two such issues: abortion rights and gun control.

Mayor Bloomberg’s endorsement, headlined as “Vote for a President to Lead on Climate Change,” arrives the same day as a Bloomberg Businessweek magazine cover story on Hurricane Sandy. The all-caps text on the striking red cover reads: “It’s Global Warming, Stupid.”